title: DNA immunization of mice against SIVmac239 Gag and Env using Rev-independent expression plasmids.
abstract: Simian immunodeficiency virus (SIV) structural gene expression, including gag and env, strictly depends on the interaction of the viral posttranscriptional regulator Rev with its target RNA, the Rev-responsive element (RRE). A small RNA element, termed the constitutive transport element (CTE), located in the 3' portion of simian retrovirus 1 (SRV-1) mRNA, can efficiently substitute for the human immunodeficiency virus (HIV) Rev-RRE interaction, and thus render HIV expression and replication Rev independent. We tested the ability of the SRV-1 CTE to drive the expression of SIVmac239 env and gag from subgenomic constructs designed for possible use in vaccine trials. In vitro expression studies showed that when the SRV-1 sequence is coupled to the SIV gag and env mRNAs, it functions in an orientation-dependent fashion, and leads to strong expression of SIV Gag and Env in human and monkey cell lines; levels of CTE-mediated protein expression were similar to those obtained with a functional Rev-RRE system. On the other hand, in murine fibroblast-like cells, SIV Gag and Env were expressed from constructs at relatively high levels even in the absence of Rev-RRE; nevertheless, their expression was increased by the presence of the SRV-1 CTE. As reported previously for HIV, the murine cell lines appeared to be defective for Rev-RRE activity, and required overexpression of Rev to induce a Rev response. Intramuscular injection of the gag-CTE and env-CTE constructs in BALB/c mice resulted in the expression of the corresponding mRNAs, and the production of anti-Gag and anti-Env antibodies, thus suggesting that these vectors might be used for genetic immunization approaches.
authors.affiliation: IST-Biotechnology Section, Padua, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Indraccolo
authors.forename: F
authors.initials: F
authors.lastname: Feroli
authors.forename: S
authors.initials: S
authors.lastname: Minuzzo
authors.forename: M
authors.initials: M
authors.lastname: Mion
authors.forename: A
authors.initials: A
authors.lastname: Rosato
authors.forename: R
authors.initials: R
authors.lastname: Zamarchi
authors.forename: F
authors.initials: F
authors.lastname: Titti
authors.forename: P
authors.initials: P
authors.lastname: Verani
authors.forename: A
authors.initials: A
authors.lastname: Amadori
authors.forename: L
authors.initials: L
authors.lastname: Chieco-Bianchi
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000276:immunology; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology; D015752:Genes, env / Q000235:genetics / Q000276:immunology; D005822:Genetic Vectors / Q000235:genetics / Q000276:immunology; D007114:Immunization / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D015301:Retroviruses, Simian / Q000235:genetics; D018449:SAIDS Vaccines / Q000276:immunology*; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D000974:Antibodies, Antinuclear; D015683:Gene Products, gag; D018449:SAIDS Vaccines; D019444:Vaccines, DNA